Cutoff control for cutting long sheets

ABSTRACT

Actuation of a brake means brings a cyclically variable drive transmission for cutoff knives to a stop at a minimum speed point in each cycle and the transmission remains stopped until a predetermined length of the web is fed past the knife bars. Thereafter, the brake is released and substantially at the same time a clutch mechanism is actuated to supply power to drive the transmission, which then drives the knife bars through a cutting operation while the web continues in motion.

tlnited States Watet [72] Inventor Albert 1F. Shields 2,193,259 3/1940 Sheperdson 83/334 X lForest lllills, NY. 2,548,427 4/1951 Fernbach 83/296 [21] Appl. No. 878,678 2,861,635 11/1958 Orr 83/299 [22] Filed Nov. 21,1969 3,176,565 4/1965 Shields 1. 83/324 [45] Patented Dec. 21,1971 3,424,041 1/1969 Giraud 1. 83/324 X [73] Assignee s & S Corrugated Paper Machinery (30., FOREIGN PATENTS 'l N Y 736,599 9/1955 Great Britain 83/335 Primary Examiner-William S. Lawson A!t0mey-Ostr0lenk, Faber, Gerb & Sofien [54] CUTOIFF CONTROL FOR CUTTING LONG SHEETS 41 Claims, 3 Drawing Figs. [52] IU'SCI 83/287 ABSTRACT: Actuation of a brake means brings a cyclically {299 83/335 variable drive transmission for cutoff knives to a stop at a [51] [m U B238 25/12 minimum speed point in each cycle and the transmission ';f-.. remains stopped until a predetermined lengljh fthe web is fed [50] Field] of Search 83/285 287 past the knife bars. Thereafter, the brake is released and sub- 334 stantially at the same time a clutch mechanism is actuated to supply power to drive the transmission, which then drives the 5 R f nc Ci ltnife bars through a cutting operation while the web continues UNITED STATES PATENTS 1,824,163 9/1931 Maier 83/335 X UT/Z2 4 flflJVJf/RGAE I L. 1 4 L I I 1 Mezz- Wflrffi/F A? F k 1 I I /:J

: r o L- 5 I I v I I 25 J I 657746! I I calm 7'54? l 25 I //YP7' [429M545 J ale/VF SPA-0 M44 PAIENTEU 05221 um mwk CUTOlFlF CONTROL FOR CUTTING LONG S'IS This application relates to cutoff knives in general, and more particularly relates to control means for cutting long length sheets from a moving web.

My U.S. Pat. No. 3,176,565 issued Apr. 6, 1965 for a Counterbalancing Means for Cutoff Knives" discloses a transmission for producing cyclically varying speeds that are readily adjustable in speed pattern within a cycle. Such types of transmission are utilized in the manufacture of corrugated sheets from a web or ribbon of corrugated board fed at a continuous predetermined speed through the cutting mechanism which cuts the board to different predetermined lengths. The cutting mechanism comprises a pair of knives mounted on individual rotating drums, one above and one below the web being cut, so that the knives cyclically engage and cut the web. The length of sheet cut by the knives depends upon the time taken for the knives to complete each revolution or cycle. Thus, in order to change sheet length, the r.p.m. of the knife drums is changed while web speed remains constant. However, during the cutting interval, it is essential that the speed of the knives be equal to or substantially equal to the linear speed of the moving web, in order to prevent either buckling of the web, which would occur if the knives moved too slowly, or ripping of the web which would occur if the knives moved too fast.

in particular, the transmission of my aforesaid US. Pat. No. 3,176,565 secures synchronism between the knives and moving web by employing the principle of a kinematic or quadric chain having four turning pairs. While such type transmission provides a relatively wide range of sheet length adjustment and exhibits a high degree of reliability, the fact remains that during normal or continuous operation of the cutoff the driving force at the knife bars or drums at the time of cutting is reduced substantially when very long length sheets are being cut. This condition does not adversely afiect performance when double face board is being cut. However, when heavier board, such as corrugated board having multiple corrugated layers, is being out, very high cutting forces are required. Because of this, long sheet lengths are often cut while the web is stopped or when the web is moved at very slow speed. Since both of these operating conditions result in low output, they are undesirable. Further, an attempt to increase cutting forces by slowing operation is, to a great extent, negated by the fact that the knife bars cannot rely upon inertia forces to help complete the cut.

In order to overcome these deficiencies of the prior art, the instant invention cuts long sheet lengths by intermittently driving a cyclically variable transmission driven cutoff. That is, the cutoff is stopped for a period during which a predetermined length of the web is advanced at paper speed. At the end of this period, the cutoff is actuated automatically and by the time the knife drums engage the web the cyclically variable transmission is up to substantially maximum speed. After each cutting the transmission is again stopped for another period of time during which a predetermined length of the web is delivered, after which the transmission is actuated and the knives cut the sheet from the web. During acceleration and deceleration of the quadric chain transmission as well as when the transmission is stopped, the web is moving at uniform high speed. It is noted that sheet length is equal to a predetermined length of the web fed while the transmission is stopped plus a length of the web fed in the interval during which the knife bars make one revolution. It is also noted that the transmission is halted at a predetermined point in the cycle to a very high degree of accuracy, made possible to a great extent by the fact that the stopping point is located near the point of minimum velocity in the cycle during continuous transmission operation and'braking takes place at a very low speed.

Accordingly, a primary object of the instant invention is to provide a novel mechanism for cutting relatively long length sheets from a moving web.

Another object is to provide apparatus of this type, in which a quadric chain or other cyclically variable speed transmission driven cutoff is stopped during each complete cycle of the cutoff while the web continues to be fed at high speed.

Still another object is to provide apparatus of this type in which the knife bar transmission is braked to a stop at a point in the cycle where velocity is normally at a minimum.

These objects as well as other objects of this invention will become readily apparent after reading the following description of the accompanying drawings in which:

FIG. I is a block diagram showing cutoff apparatus constructed in accordance with teachings of the instant invention.

FIG. 2 is a knife bar velocity diagram.

FIG. 3 is a fragmentary side elevation of board having multiple corrugated layers.

Now referring to the figures. The apparatus of HG. ll receives web or ribbon 11, moving in the direction indicated by arrow A, and produces sheets 112 of predetermined length by cutting web 11 transverse to its direction of movement A. More particularly, feeder M continuously moves web l l from left to right with respect to FIG. l between knife bars or drums I5, 16 of adjustable cyclically variable transmission driven cutofi 20, of a type described in detail in my aforesaid US. Pat. No. 3,176,565. As will hereinafter be seen, the knives carried by bars 15, 16 periodically engage web llll to cut same transverse to the direction of movement A to produce sheets 112 that are removed by takeofi device 19. As seen in FIG. 3,

sheet Ill is constructed of seven layers of material, three of which are corrugated. This produces very stiff board which requires very high cutting forces.

Web feeder I4 is directly driven by input drive 22 which also drives variable speed unit 23. Clutch brake unit 25 is interposed between variable speed unit 23 and adjustable cutoff 20. Unit 25 consists of clutch section 26 and brake section 27.

Clutch 26 and brake 27 are coordinated in a manner well known to the art, so that when clutch in is operated into engagement, brake 27 is released essentially simultaneously. Conversely, when brake 27 is actuated, clutch 26 is released essentially simultaneously.

For reasons which will hereinafter be explained, measuring means or settable counter 28 includes an input derived from signals produced by web feeder M and an output which is used to actuate clutch 26 and atthe same time release brake 27. As will also hereinafter be seen, actuation of brake 27 to stop cutoff 20 and the release of clutch 26 are controlled by signals derived from cutoff 20.

In operation, after each cutting operation performed by cutoff 20 the latter is stopped. However, feeder l4 continues to deliver web 11 at high speed through cutoff 2th. The length of web ll delivered during this period while cutoff Zlll is stopped is determined by the setting of counter 22%, which upon counting after receipt of a predetermined number of signals, such as shaft revolution counts, actuates clutch is and releases brake 27. This operation drives cutofi 20 into operation with the knives thereof cutting web 11 to produce sheet 112. After the cutting operation, a signal derived from the position of knife drums l5, 16 is utilized to apply brake 27 and release clutch 26, with cutoff 20 being brought to a stop at a predetermined location or point in its cycle.

As is well known to the art, when the cutoff 2% is operated continuously or normally, knife drums 115, lb rotate at a speed which varies within each cycle. If a quadric chain linkage is used to drive the cutoff, its velocity diagram will be as illustrated in FIG. 2. In particular, cutting takes place at or near maximum velocity B for knife bars 15, I6. Brake 2'7 is applied and actual stopping of cutoff 20 occurs at portion C of the cycle where velocity is minimum.

It is noted that the length of sheet 12 is a function of the count made by settable counter 2% plus the time knife bars l5, l6 require to make one revolution. F or best cutting advantage cutoff 20 is set for normal operation at a sheet length where a high cutting force is present. Counter 2% is then set to control a major portion of the length of sheet 12 with final adjustments being made by slight adjustment made by varying the Reeves drive of cutoff 20. Sheet length accuracy is maintained by stopping cutoff 20 at a low point on the normal velocity diagram. It is also noted that after settable counter 2% uncounts and transmits a signal causing engagement of clutch 2b and release of brake 27, counter 28 automatically resets and then stands idle until receipt of a signal from cutoff 20. Such signal fed to counter 28 indicates that sheet 12 has been severed from web 11 and cutoff 20 is stopped.

While specific reference in the foregoing specification has been made to a quadric chain drive transmission, the latter may be replaced by a slotted crank or elliptical gear type transmission.

Further, while operation of the apparatus in FIG. 1 has been described as controlling sheet length by starting the counter when the knife bars are stopped, comparable results may be achieved by starting the counter when the web is cut.

Although this invention has been described with respect to a particular embodiment, it should be understood that many variations and modifications will now be obvious to those skilled in the art and therefore the scope of this invention is limited not by the specific disclosure herein, but only by the appended claims.

The embodiments of the invention in which an exclusive privilege or property is claimed are defined as follows:

1. Apparatus for transforming a moving elongated web into sheets, said apparatus comprising feeding means for moving the web longitudinally at uniform speed, an adjustable knife means for cutting the moving web transverse to the axis thereof to produce sheets, input power means to drive said feeding means and said knife means, a brake actuable to stop said knife means following each cutting of the web by said knife means, a disengageable clutch interposed between said power means and said knife means, said feeding means moving said web when said clutch is both engaged and disengaged,

a settable measuring means which controls engagement of said clutch and release of said brake in response to signals derived from said feeding means whereby said knife means is actuated to cut said web into sheets each having a length determined by the setting of said measuring means plus the movement of said web in the interval required to operate said knife means through a cycle, afier each cut by said knife means said feeding means moving a preselected length of said web past said knife means while said clutch is disengaged and said brake is engaged, and said feeding means also moving an additional preselected length of said web past said knife means while the clutch is engaged and said knife means is operated through a cycle, whereby each of said sheets is of a length equal to said preselected length plus said additional preselected length.

2. Apparatus as set forth in claim 1, in which said knife means is constructed with cutting elements that operate at a speed that varies within each cycle of uniform input speed supplied by said input power means to said knife means, said cutting elements engaging said web when said cutting elements are approximately at maximum speed within each cycle, said brake acting to stop said knife means during a portion of said cycle when said cutting elements are approximately at minimum speed.

3. Apparatus as set forth in claim 2, in which the measuring means includes a counter.

4. Apparatus as set forth in claim 1, in which said counter commences operation when said brake is operated into engagement.

i i I l UNITED STATES PATENT UHPEQE CERTIFICATE OF ETW Patent NO. 3,628,410 Dated December 21, 1971 inventorfi-ad Albert P. Shields It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

In Column 4, line 26, "1" Should be --3-- Signed and sealed this 6th day of March 1973.

(SEAL) Attest:

EDWARD M.FLETCHER,JR. ROBERT GOTTSCHALK Attesting Officer Commissioner of Patents ORM PO-1U5O (1G-6S) USCOMM-DC 60376-P69 w us GOVERNMENT PRINTING OFFICE I969 O',66334 

1. Apparatus for transforming a moving elongated web into sheets, said apparatus comprising feeding means for moving the web longitudinally at uniform speed, an adjustable knife means for cutting the moving web transverse to the axis thereof to produce sheets, input power means to drive said feeding means and said knife means, a brake actuable to stop said knife means following each cutting of the web by said knife means, a disengageable clutch interposed between said power means and said knife means, said feeding means moving said web when said clutch is both engaged and disengaged, a settable measuring means which controls engagement of said clutch and release of said brake in response to signals derived from said feeding means whereby said knife means is actuated to cut said web into sheets each having a length determined by the setting of said measuring means plus the movement of said web in the interval required to operate said knife means tHrough a cycle, after each cut by said knife means said feeding means moving a preselected length of said web past said knife means while said clutch is disengaged and said brake is engaged, and said feeding means also moving an additional preselected length of said web past said knife means while the clutch is engaged and said knife means is operated through a cycle, whereby each of said sheets is of a length equal to said preselected length plus said additional preselected length.
 2. Apparatus as set forth in claim 1, in which said knife means is constructed with cutting elements that operate at a speed that varies within each cycle of uniform input speed supplied by said input power means to said knife means, said cutting elements engaging said web when said cutting elements are approximately at maximum speed within each cycle, said brake acting to stop said knife means during a portion of said cycle when said cutting elements are approximately at minimum speed.
 3. Apparatus as set forth in claim 2, in which the measuring means includes a counter.
 4. Apparatus as set forth in claim 1, in which said counter commences operation when said brake is operated into engagement. 